The invention relates to a scissors jack for a vehicle and more particularly is concerned with a scissors jack which is adapted to be permanently mounted on the bottom frame of the vehicle to stabilize and level the vehicle.
Current interest in camping and recreational vehicles has brought about a need for more efficient stabilizing and leveling of the vehicles at a camp site. Previous jacks have been developed to solve this problem; however, they have several disadvantages including positioning the jacks at the proper point under the vehicle each time they are desired to be utilized. These need not be exhaustably discussed, but a brief mention of some will emphasize the advantages of the invention.
The scissors jack structure is generally represented by the embodiment described in U.S. Pat. No. 1,709,746 which has interchangeable outer arm elements. The arms of this jack are eight duplicate interchangeable elements with teeth on one end of the arms with the actuating rod exposed. This jack is placed in the proper position under a vehicle each time it is to be used. It has spacers between the arms to keep the teeth engaged, but does not have an internally placed strap between the pivot points at the ends of the arms.
In U.S. Pat. No. 2,479,362, a structure for engaging a threaded rod through only one pivotally mounted internally threaded nut is described. Again, this jack is intended to be positioned each time it is to be used and it also has spacers mounted on the pivot pins between the arms, but no straps on the inside of the arms. Here again, the arms are eight separate elements with the actuating rod exposed.
In U.S. Pat. No. 2,581,706 a rather complicated leveling and stabling jack is disclosed. This jack has eight L-shaped members and does have straps between the pivot points, but not on the mounting member and baseplate. This jack is adapted to substantially enclose the threaded rod and is adapted to be mounted on the underneath side of a vehicle like that of the invention, but it does so with a distinctly different structure.
U.S. Pat. No. 2,920,871 discloses a jack for an automobile very similar to previously mentioned U.S. Pat. No. 1,709,746. Again, the jack disclosed has eight separate arm elements leaving the threaded rod exposed in all positions of the jack. In this structure a separate tongue is disclosed, which is to be mounted onto the bottom of the vehicle so that the jack may be engaged with the tongue when it is to be utilized. Again, no straps are disclosed engaging the insides of the pairs of pivot points.
U.S. Pat. No. 3,317,187 discloses a scissors type jack to be put into position each time it is desired to be utilized. This jack has seven arm elements one of which is a channel-shaped member. The threaded rod substantially is exposed in all positions of the jack and no engagement straps are disclosed.
In U.S. Pat. No. 3,857,548 a scissors jack is disclosed which has a load supporting member, but it is adapted to be placed in position each time it is desired to be utilized. This jack again has eight separate arm members exposing the actuating rod and does not disclose any strap on the inside of the pivot points connecting the pairs of pivot points together.
None of these prior art structures discloses means for substantially enclosing the threaded rod to protect it from the elements and other foreign objects when it is mounted on the underneath side of the vehicle in the combination of the invention. The seven or eight separate arm elements do not have the strength and simplicity of the four channel-shaped scissors arms of the invention. The particular T-shaped mounting bracket also is not disclosed by U.S. Pat. No. 2,581,706 which does suggest mounting the jack permanently to the underneath side of a vehicle. None of the structures discloses straps between riveted pivot points to keep the teeth intermeshed or slots in the baseplate or mounting member to provide relief for the teeth of the scissors arms.